76 ideas
| 13466 | We are all post-Kantians, because he set the current agenda for philosophy [Hart,WD] |
| 13477 | The problems are the monuments of philosophy [Hart,WD] |
| 13515 | To study abstract problems, some knowledge of set theory is essential [Hart,WD] |
| 7113 | Phenomenology assumes that all consciousness is of something [Sartre] |
| 13469 | Tarski showed how we could have a correspondence theory of truth, without using 'facts' [Hart,WD] |
| 13504 | Truth for sentences is satisfaction of formulae; for sentences, either all sequences satisfy it (true) or none do [Hart,WD] |
| 13503 | A first-order language has an infinity of T-sentences, which cannot add up to a definition of truth [Hart,WD] |
| 13500 | Conditional Proof: infer a conditional, if the consequent can be deduced from the antecedent [Hart,WD] |
| 13502 | ∃y... is read as 'There exists an individual, call it y, such that...', and not 'There exists a y such that...' [Hart,WD] |
| 13456 | Set theory articulates the concept of order (through relations) [Hart,WD] |
| 13497 | Nowadays ZFC and NBG are the set theories; types are dead, and NF is only useful for the whole universe [Hart,WD] |
| 13443 | ∈ relates across layers, while ⊆ relates within layers [Hart,WD] |
| 13442 | Without the empty set we could not form a∩b without checking that a and b meet [Hart,WD] |
| 13493 | In the modern view, foundation is the heart of the way to do set theory [Hart,WD] |
| 13495 | Foundation Axiom: an nonempty set has a member disjoint from it [Hart,WD] |
| 13462 | With the Axiom of Choice every set can be well-ordered [Hart,WD] |
| 13461 | We can choose from finite and evident sets, but not from infinite opaque ones [Hart,WD] |
| 13516 | If we accept that V=L, it seems to settle all the open questions of set theory [Hart,WD] |
| 13441 | Naïve set theory has trouble with comprehension, the claim that every predicate has an extension [Hart,WD] |
| 13494 | The iterative conception may not be necessary, and may have fixed points or infinitely descending chains [Hart,WD] |
| 13460 | 'Well-ordering' must have a least member, so it does the natural numbers but not the integers [Hart,WD] |
| 13458 | A partial ordering becomes 'total' if any two members of its field are comparable [Hart,WD] |
| 13457 | A 'partial ordering' is irreflexive and transitive; the sets are ordered, but not the subsets [Hart,WD] |
| 13490 | Von Neumann defines α<β as α∈β [Hart,WD] |
| 13481 | Maybe sets should be rethought in terms of the even more basic categories [Hart,WD] |
| 13506 | The universal quantifier can't really mean 'all', because there is no universal set [Hart,WD] |
| 13513 | Models are ways the world might be from a first-order point of view [Hart,WD] |
| 13505 | Model theory studies how set theory can model sets of sentences [Hart,WD] |
| 13511 | Model theory is mostly confined to first-order theories [Hart,WD] |
| 13512 | Modern model theory begins with the proof of Los's Conjecture in 1962 [Hart,WD] |
| 13496 | First-order logic is 'compact': consequences of a set are consequences of a finite subset [Hart,WD] |
| 13484 | Berry's Paradox: we succeed in referring to a number, with a term which says we can't do that [Hart,WD] |
| 13482 | The Burali-Forti paradox is a crisis for Cantor's ordinals [Hart,WD] |
| 13507 | The machinery used to solve the Liar can be rejigged to produce a new Liar [Hart,WD] |
| 13459 | The less-than relation < well-orders, and partially orders, and totally orders the ordinal numbers [Hart,WD] |
| 13463 | There are at least as many infinite cardinals as transfinite ordinals (because they will map) [Hart,WD] |
| 13491 | The axiom of infinity with separation gives a least limit ordinal ω [Hart,WD] |
| 13492 | Von Neumann's ordinals generalise into the transfinite better, because Zermelo's ω is a singleton [Hart,WD] |
| 13446 | 19th century arithmetization of analysis isolated the real numbers from geometry [Hart,WD] |
| 13509 | We can establish truths about infinite numbers by means of induction [Hart,WD] |
| 13474 | Euclid has a unique parallel, spherical geometry has none, and saddle geometry has several [Hart,WD] |
| 13471 | Mathematics makes existence claims, but philosophers usually say those are never analytic [Hart,WD] |
| 13488 | Mass words do not have plurals, or numerical adjectives, or use 'fewer' [Hart,WD] |
| 7114 | The consciousness that says 'I think' is not the consciousness that thinks [Sartre] |
| 7112 | The Cogito depends on a second-order experience, of being conscious of consciousness [Sartre] |
| 7119 | Is the Cogito reporting an immediate experience of doubting, or the whole enterprise of doubting? [Sartre] |
| 13480 | Fregean self-evidence is an intrinsic property of basic truths, rules and definitions [Hart,WD] |
| 13476 | The failure of key assumptions in geometry, mereology and set theory throw doubt on the a priori [Hart,WD] |
| 7125 | A consciousness can conceive of no other consciousness than itself [Sartre] |
| 7122 | We can never, even in principle, grasp other minds, because the Ego is self-conceiving [Sartre] |
| 7108 | The eternal truth of 2+2=4 is what gives unity to the mind which regularly thinks it [Sartre] |
| 7111 | Consciousness exists as consciousness of itself [Sartre] |
| 22226 | Since we are a consciousness, Sartre entirely rejected the unconscious mind [Sartre, by Daigle] |
| 7107 | Intentionality defines, transcends and unites consciousness [Sartre] |
| 7109 | If you think of '2+2=4' as the content of thought, the self must be united transcendentally [Sartre] |
| 7106 | The Ego is not formally or materially part of consciousness, but is outside in the world [Sartre] |
| 7117 | How could two I's, the reflective and the reflected, communicate with each other? [Sartre] |
| 7123 | Knowing yourself requires an exterior viewpoint, which is necessarily false [Sartre] |
| 22225 | My ego is more intimate to me, but not more certain than other egos [Sartre] |
| 7116 | When we are unreflective (as when chasing a tram) there is no 'I' [Sartre] |
| 7124 | The Ego never appears except when we are not looking for it [Sartre] |
| 7120 | It is theoretically possible that the Ego consists entirely of false memories [Sartre] |
| 7110 | If the 'I' is transcendental, it unnecessarily splits consciousness in two [Sartre] |
| 7115 | Maybe it is the act of reflection that brings 'me' into existence [Sartre] |
| 7121 | The Ego only appears to reflection, so it is cut off from the World [Sartre] |
| 13475 | The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD] |
| 7096 | We may still admire a person's character even if the traits are involuntary [Statman] |
| 7098 | There is a new sort of moral scepticism, about the possibility of moral theories [Statman] |
| 7099 | With a broad concept of flourishing, it might be possible without the virtues [Statman] |
| 7100 | Virtue theory isn't a genuine ethical theory, because it doesn't have universal application [Statman] |
| 7102 | Promises create moral duties that have nothing to do with character [Statman] |
| 7095 | Moral education is better by concrete example than abstract principle [Statman] |
| 7094 | Friends express friendship even when no utility is involved [Statman] |
| 7104 | The ancients recognised imperfect duties, but we have added perfect duties like justice [Statman] |
| 7093 | Behaviour may be disgusting or inhumane, but violate no duty [Statman] |
| 7103 | Abortion issues focus on the mother's right over her body, and the status of the foetus [Statman] |